1. Field of the Invention
The present invention generally relates to constant velocity joints and more particularly, relates to a high angle, high-speed constant velocity joint.
2. Description of the Related Art
Constant velocity joints (CV joints) are common components in automotive vehicles. Typically, constant velocity joints are employed where transmission of a constant velocity rotary motion is desired or required. Common types of constant velocity joints are a plunging tripod, a fixed tripod, a plunging ball joint, and a fixed ball joint. These joints can be used in front wheel drive vehicles, or rear wheel drive vehicles and on the propeller shafts found in rear wheel drive, all wheel drive and four wheel drive vehicles. The plunging constant velocity joints allow for axial movement during the operation without the use of slip splines, but sometimes initiate forces that result in vibration and noises. The plunging types allow angular displacement along with the axial displacement along two axes thereof. The fixed type constant velocity joints generally only allow angular displacement between two axes. The fixed constant velocity joints are better situated for higher operating angles than that of a plunging type constant velocity joint. All of these constant velocity joints are generally grease lubricated for life and sealed by a sealing boot when used on drive shafts. Thus, the constant velocity joints are sealed in order to retain grease inside the joint while keeping contaminates and foreign matter, such as dirt and water, out of the joint. The sealing protection of the constant velocity joint is necessary because contamination of the inner chamber causes internal damage and destruction of the joint which increases heat and wear on the boot, thus inevitably leading to premature boot and grease failures and hence failure of the overall joint. The problem of higher temperatures in high speed fixed constant velocity joint is greatly enhanced at the higher angles. Thus, the increased temperatures because of higher angles along with increased stresses on the boot because of higher angles may result in premature failures of the prior art constant velocity joints.
Generally, prior art fixed type constant velocity joints included a bulky and heavy outer race having a spherical inner surface and a plurality of grooves on a surface therein. The joints also include an inner race, having a spherical outer surface with guide grooves formed therein. Most of the prior art fixed type constant velocity joints used six torque transmitting balls, which are arranged between the guide grooves and the outer and inner race surfaces of the constant velocity joint by a cage retainer. The balls allow a predetermined displacement angle to occur through the joint thus transmitting a constant velocity through the shafts of the automotive drive train system.
Therefore, there is a need in the art for a constant velocity joint that is capable of high angle and high-speed use. There is also a need in the art for a constant velocity joint that has a smaller package, increased efficiency and better thermal characteristics during high-speed, high angle operation.
One object of the present invention is to provide an improved constant velocity joint.
Another object of the present invention is to provide a high angle, high-speed opposing track constant velocity joint.
Yet a further object of the present invention is to provide a constant velocity joint that centers the cage and supports the cage by an inner race spherical surface alone.
Still a further object of the present invention is to provide a constant velocity joint that uses axially opposed tracks.
Yet a further object of the present invention is to provide a constant velocity joint that uses double offset tracks.
Still another object of the present invention is to provide a constant velocity joint that is configured such that the boot will be able to set within the cage and move closer to the center line of the joint.
Still a further object of the present invention is to provide a constant velocity joint that is balanced such that the shaft and tube will be capable of moving through the outer race in the event of a collision.
Still another object of the present invention is to provide a constant velocity joint that is capable of assembly without the use of cage grooves.
To achieve the foregoing objects, a constant velocity joint for use in a vehicle includes an outer race and cage arranged within the outer race. The constant velocity joint also includes an inner race having an outer surface wherein that outer surface alone centers and supports the cage. A plurality of balls are arranged within the cage. The constant velocity joint also includes a shaft connected to the inner race and a boot cover contacting the outer race. A boot is arranged between the boot cover and the shaft while a cap is secured to the outer race on a side opposite of the boot cover.
One advantage of the present invention is that the constant velocity joint can be used for high angle, high speed applications and may include from six to ten torque transmitting balls.
A further advantage of the present invention is that the constant velocity joint uses a cage that is centered and supported by the inner circle surface alone insuring there is no contact between the outer race and the cage thus improving joint efficiency and reducing boot and grease thermal failures.
Still another advantage of the present invention is that the constant velocity joint uses axially opposed tracks which will result in a decrease in cage forces that allows for the elimination of guide spheres and improves the efficiency and thermal characteristics of the joint.
Yet another advantage of the present invention is that the constant velocity joint uses double offset tracks, which includes both a radial offset and an axial offset in order to flatten the tracks, promote easier rolling, provide better outer ball track edge support and therefore allow the joint to articulate to a higher angle while maintaining the improved efficiency and durability while allowing the joint to articulate to a higher angle.
Still another advantage of the present invention is the use of a constant velocity joint that allows the boot to set within the outer diameter of the cage thus moving the boot closer to the center line of the joint thus decreasing the package size and reducing boot stress.
Yet another advantage of the present invention is a constant velocity joint that will allow the tube/shaft to be plunged through an outer race bore in the event of a collision.
Still another advantage of the present invention is the use of a constant velocity joint that will allow assembly of the inner race into the cage without the use of cage grooves thus increasing the strength of the overall structure of the constant velocity joint.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and appended claims, taken in conjunction with the accompanying drawings.